package com.vc.web.servlet;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class GZipFilter implements Filter {

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		HttpServletRequest req = (HttpServletRequest) request;
		HttpServletResponse res = (HttpServletResponse) response;
		if (isGzipSupported(req)) {
			GZipResponse zipResponse = new GZipResponse(res);
			res.setHeader("Content-Encoding", "gzip");
			chain.doFilter(request, zipResponse);
			zipResponse.flush();
		} else {
			chain.doFilter(request, response);
		}
	}

	private boolean isGzipSupported(HttpServletRequest req) {
		String browserEncodings = req.getHeader("Accept-Encoding");
		return ((browserEncodings != null) && (browserEncodings.indexOf("gzip") != -1));
	}

	public void destroy() {

	}

	public void init(FilterConfig fConfig) throws ServletException {

	}
}